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Table 1 Comparison of baseline characteristics and clinical outcomes of patients with methicillin-susceptible S. aureus bacteremia who received empiric antimicrobial therapy with β-lactams or vancomycin

From: Comparative effectiveness of β-lactam versus vancomycin empiric therapy in patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia

Patient characteristics β-lactama (n = 131) Vancomycina (n = 124) p value
Age (mean ± standard deviation in years) 53.2 ± 16.5 59.4 ± 18.3 0.005
Males 83 (63.4) 86 (69.4) 0.31
Community-onset 105 (80.2) 84 (67.8) 0.03
Hospital-onset 26 (19.8) 40 (32.3) 0.03
HIV infection 11 (8.4) 8 (6.5) 0.55
Hepatitis C infection 29 (22.1) 28 (22.6) 0.93
Immunocompromised 14 (10.7) 10 (8.1) 0.47
Alcohol or illicit drug abuse 41 (31.3) 38 (30.6) 0.91
Intravenous drug use 29 (22.1) 29 (23.4) 0.81
Charlson comorbidity index (median with IQR) 3 (1.0–6.0) 4 (1.0–7.0) 0.001
Pitt bacteremia score (median with IQR) 1 (0–2) 1 (0–2) 0.17
Infectious diseases consultation 98 (74.8) 80 (64.5) 0.07
Source of bacteremia
 Central or peripheral line 20 (15.3) 22 (17.7) 0.62
 Skin and soft tissue 31 (23.7) 16 (12.9) 0.04
 Intravenous drug use 21 (16.0) 19 (15.3) 1.00
 Bone or joint infection 18 (13.7) 10 (8.1) 0.16
 Lung 4 (3.1) 3 (2.4) 1.00
 Other 12 (9.2) 10 (8.1) 0.83
 Unknown 25 (19.1) 44 (35.5) 0.005
Infective endocarditis 24 (18.3) 12 (9.7) 0.05
Metastatic complications 40 (30.5) 27 (21.8) 0.11
Surgical source control 33 (25.2) 19 (15.3) 0.05
Recurrent infection at 6 months 4 (3.1) 4 (3.2) 1.00
Empiric antimicrobials
 Vancomycin 88 (67.2) 123 (99.2) <0.001
 Daptomycin 2 (1.5) 0 0.50
 Linezolid 2 (1.5) 0 0.50
 Cloxacillin or cefazolin 131 (100) 0 <0.001
 3rd generation cephalosporin 40 (30.5) 0 <0.001
 Piperacillin–tazobactam 33 (25.2) 0 <0.001
 Ticarcillin–clavulanic acid 3 (2.3) 0 0.25
 Carbapenem 2 (1.5) 0 0.50
 Otherb 47 (35.9) 66 (53.2) 0.01
Blood culture time to positivity (median hours with IQR) 20 (16.5–24.9) 18.3 (15.9–23.5) 0.17
Duration of empiric therapy (median hours with IQR) 54 (42.0–69.0) 48 (29.6–75.8) 0.28
Duration of definitive therapy (median days with IQR) 31.5 (13.0–42.0) 28 (10.0–42.0) 0.17
Time to receipt of empiric therapy (median hours with IQR) 2 (0–7) 20.9 (4.2–28.3) <0.001
Time to receipt of β-lactam (median hours with IQR) 3 (0.2–16.3) 68.2 (51.5–95.4) <0.001
Time to receipt of cloxacillin or cefazolin (median hours with IQR) 21.0 (4.4–31.2) 68.3 (51.6–95.4) <0.001
Primary outcome
 28-day mortality 7 (5.3) 11 (8.9) 0.27
Secondary outcomes
 90-day mortality 14 (10.7) 22 (17.7) 0.11
 Duration of bacteremia (median hours with IQR)c 70.7 (46.9–119) 97.1 (61.6–148) 0.007
 ≥3 days 58 (50) 72 (63.2) 0.047
 Hospital length of stay (median days with IQR)d 17 (11–36) 17 (12–36.5) 0.84
  1. IQR interquartile range
  2. aVariables are displayed as counts and percentages in parentheses unless otherwise specified
  3. bOther antimicrobials used during empiric and definitive therapy included rifampin, aminoglycosides, fluoroquinolones, macrolides, trimethoprim-sulfamethoxazole, and clindamycin
  4. c15 and 10 patients from the β-lactam and vancomycin group respectively were excluded from the analysis due to lack of follow-up blood cultures
  5. d12 and 19 patients from the β-lactam and vancomycin group respectively were excluded from the analysis due to death during hospital admission